It is desirable in fluid handling conduits to ensure that the connectors used have their male and female portions properly coupled together. A faulty connector enables an associated host system to leak fluid. This can be particularly disadvantageous when the system is under pressure and the leaking connector expels the pressurized fluid.
In the quick connector field, where male and female portions of the connectors are held together by friction locking members, it is important that the male and female portions be properly coupled. To ensure proper coupling, the installer may tug on or manipulate the connector to make sure that it is fully engaged. Also, visual types of inspecting devices enable the installer to confirm that the male and female portions are properly coupled together from observation alone.
U.S. Pat. No. 4,925,217, issued to Ketcham, discloses a quick connector with a visual checking feature having a deformable member assembled within the fitting that includes elongated members extending out of the housing between the male and female portions prior to coupling and that are retracted, and no longer visible, once the coupling has been accomplished. Although this type of connector may work satisfactorily for its intended purpose, designers are always trying to improve the field. Furthermore, designs such as that employed by Ketcham provide only relatively small axial movement of the indicator member, which, when employed with relatively low cost, high tolerance manufacturing, limits the reliability of the perceived indication and, alternatively, adds additional expense to a more highly refined design. Lastly, the spring-like operation of Ketcham's vaulted annular member requires use of relatively expensive materials and can introduce additional failure modes, such as fracture of one of the legs, which could interfere with proper coupling operation.
A related problem stems from dual aspects of commercially available quick connect devices, to wit: high volume and low sale price frequently necessitating the use of inexpensive, somewhat pliable materials, and complex contours of extremely small inter-fitting components. These aspects collectively increase the likelihood of mis-assembly. High volume production techniques, including automated assembly tends to aggravate the problem wherein mis-assembly or impermissible dimensional variations of the components is difficult to detect.
Further problems may be encountered when using conventional quick connect devices with multilayer tubing. Multilayer tubing is utilized to meet current government standards in fluid handling. Conventional devices may not always be compatible with multilayer tubing in that a proper seal is not necessarily maintained and some devices will potentially damage the integrity of the tubing.